Think it through.
Start with a prediction. Notice what you assume before you touch the code.
Use AI to ship.
Practice to stay sharp.
Short TypeScript workouts for the skills you want to keep. Build your own judgment, one small practice at a time.
One complete guided exercise today. A broader program catalog is planned.
A little practice. A stronger instinct.
For developers who want to understandthe code they ship.
YOUR FIRST REP
Make every payment state explicit
A payment can be paid, declined, or pending. What happens when the switch forgets one state?
type PaymentResult =
| { status: 'paid'; receiptId: string }
| { status: 'declined'; reason: string }
| { status: 'pending' };
function describe(result: PaymentResult): string {
switch (result.status) {
case 'paid': return 'Receipt: ' + result.receiptId;
case 'declined': return 'Declined: ' + result.reason;
default: return 'Unknown payment status';
}
}What message does a pending payment receive?
Make room for a little practice.
Work the problem.
Read a focused TypeScript example, choose a repair and check its behavior in the browser.
Keep the lesson.
Write a reflection. Give your future self something useful to return to.
THE FIRST TRAINING BLOCK
TypeScript.
Stronger at the edges.
Practice the details that make everyday code more reliable: types, async behavior and the assumptions in between.
Planned as four weeks and 12 short workouts within Level 3. Completing this block will not mean completing the whole level.
Explore the previewA look inside the program
Types & contracts
Question your assumptions
Async & state
Handle what happens out of order
Edges & behavior
Think beyond the happy path
The discriminated-union exercise is ready to try. The full block is in development.
See the 12-session outlineTHE PROGRAM PATH
Practice for where you are—and where you’re going.
Five planned levels cover a route from first programs to system-wide decisions. They describe readiness in a subject, not a universal rank.
Explore all program details- 01
Foundations
Create a small program from a clear brief, check its behaviour and explain how it works.
- 02
Practical Developer
Turn a small feature brief into understandable, typed and tested behaviour.
- 03
Reliable Developer
Diagnose realistic defects and preserve correct behaviour under boundaries, asynchronous changes and partial failure.
- 04
Advanced Engineering
Improve a service or application using explicit design, performance and operational tradeoffs.
- 05
Systems and Technical Judgment
Compare system designs, investigate ambiguous failures and plan safe evolution under real constraints.
The catalog can grow through new tracks and editions while preserving completed progress. Personal routes and shared programs are a future direction, not an available feature today.
Tell us what you want to practiseTypeScript first. More languages can follow.
We’re starting with JavaScript and TypeScript examples. Use the waitlist to tell us which language or track would make the next program useful to you.
A few things
you might be
wondering.
Who is CodeStamina for?
The planned catalog ranges from first-program Foundations to advanced systems judgment. Levels describe readiness in a subject, not seniority. Today’s TypeScript preview is best for developers who can already read functions, objects and simple control flow.
How long is a workout?
The guided preview takes about 8–12 minutes. Take it at your own pace; the aim is thoughtful practice.
What can I try today?
Complete a guided TypeScript exercise on discriminated unions and exhaustive switches: predict the behavior, compare repairs, check four requirements and keep your takeaway. No sign-in needed.
Is this an interview-prep course?
The focus is everyday engineering judgment: reading code, spotting assumptions and reasoning about behavior. The planned program is built around short, deliberate practice.
Your next small step
starts here.
Try one guided rep now, or tell us what you want to practise next.
Early preview · The broader catalog is planned